Bantam 1.3i 2008: "Overheating" & noisy fan/engine

I recently had a bad water leak. Found that the heater housing had
perished. Temporary measure was to block the two pipes from the
thermostat housing to the heater housing by using spark plugs.
Turned out the thermostat housing needed replacing.
Looped the one heater pipe between the two fittings from the thermostat
housing to the heater housing (bypasses heater so I can't use my heater at
the moment, until I can get another heater housing).
Car still over heating a little - was sitting at the 2/3 third to 3/4 mark on the
heat gauge. Mechanic who replaced thermostat housing didn't attach one
line properly (thin one of two lines, fits on the left) over the engine (think it's
the airline), which has helped keep the heat gauge to stay at half to maybe
2/3 now.  The minute the line was properly attached, the revs dropped.
Since the water leak, the engine (fan?) is making a very loud noise when
the fan comes on. Nothing touching the fan to cause the noise. Never blew
the head - because there's no oil and water mixed. Water bottle was dry
and engine extremely hot, but needle fell just short of the red on the heat
gauge when the water problem occurred. Engine never made a loud noise
before this water leak.
Any idea on what can be making the noise and overheating a little?
Will greatly appreciate some help,
From a desperate single mom with limited finances